复杂地质条件下拱坝整体稳定三维地质力学模型试验研究

Experimental study of 3d geomechanical model on global stability of an arch dam under complex geological condition

针对某高拱坝坝址区地质构造复杂,两岸坝肩岩体内存在断层、煌斑岩脉、层间挤压带、深部裂隙等各类软弱结构面等工程地质问题,本文利用三维地质力学模型试验技术,采用强度储备与超载相结合的综合法试验方法,研究了坝体和坝肩从加荷到破坏的整个过程,试验中充分考虑了影响坝肩坝基稳定的各种因素,既考虑拱坝上游超载情况,同时还重点模拟两坝肩岩体中软弱结构面强度弱化的影响。通过试验获得了坝肩坝基的变形及分布特征、失稳的破坏形态和破坏机理。试验结果表明:拱坝整体稳定安全度约为4.7～4.9,拱坝的基础处理效果较好,并针对坝肩的薄弱环节提出了加固处理措施建议。

Aiming at the complex geological structure of a high arch dam in dam site area, there are many different weak structural planes in rock mass of the dam foundation such as fault, lamprophyre, inner layer extrusion zone, deep cracks, which are disadvantageous to the stability of the dam foundation and abutment. The whole process of the arch dam and abutments from loading to failure are studied by three dimensional geomechanical model test. The model considers various factors influencing the stabilities of dam foundation and abutment including overloading as well as the strength decreasing of weak structural planes in the reck mass of the dam foundation. The comprehensive method that considers both overloading and strength decreasing is applied to the model. The deformation characters, failure conditions and mechanisms of the dam foundation and abutment are achieved. The results show that the global safety factor of the dam is 4.7 - 4.9, and reinforcing treatment effect of arch dam foundation is better. In addition, the reinforcing measures for the weak areas are advised.